export function addClass(el,className){
    if(hasClass(el,className)){
        return
    }
    let newClass=el.className.split(' ')
    newClass.push(className)
    el.className=newClass.join(' ')
}

export function hasClass(el,className){
    let reg=new RegExp('(^|\\s)'+className+'(\\s|$)')
    return reg.test(el.className);
}